/*!	 quick_rng.h
**	 Template Header
**
**	Copyright (c) 2002-2005 Robert B. Quattlebaum Jr., Adrian Bentley
**	Copyright (c) 2007 Chris Moore
**
**	This package is free software; you can redistribute it and/or
**	modify it under the terms of the GNU General Public License as
**	published by the Free Software Foundation; either version 2 of
**	the License, or (at your option) any later version.
**
**	This package is distributed in the hope that it will be useful,
**	but WITHOUT ANY WARRANTY; without even the implied warranty of
**	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
**	General Public License for more details.
**
*/

#ifndef __SYNFIG_QUICK_RNG_H
#define __SYNFIG_QUICK_RNG_H

#include <stdint.h>

// A fast 32-bit linear congruential random number generator
class quick_rng
{
    uint32_t next;
public:
    quick_rng(uint32_t seed = 0): next(seed) { }

    void set_seed(uint32_t x)
    {
        next = x;
    }

    uint32_t i32()
    {
        static const uint32_t a(1664525);
        static const uint32_t c(1013904223);

        return next = next * a + c;
    }

    uint32_t i16()
    {
        return i32() >> 16;
    }

    float f()
    {
        static const float m(int(65535));

        return float(i16()) / m;
    }

    uint32_t operator()(const uint32_t& m)
    {
        if (m == 65536) {
            return i16();
        } else if (m <= 65536) {
            return i16() % m;
        } else {
            return i32() % m;
        }
    }
};

#endif